This invention relates to a seal for liquid materials and more particularly relates to seals of the type which are broken by any suitable puncturing device. In the prior art seals which were broken by puncturing devices resulted in a hole in the seal which permitted liquid to flow through the hole to the exterior of the container or conduit to which the seal was applied. A serious disadvantage of this type of prior art seal is that the act of puncturing the seal results in a raised portion inside the container seal surrounding the position of the puncture. The raised portion results in a wall or dam which will hold liquid thus preventing all of the liquid from flowing through the hole in the punctured seal. This residual liquid creates a serious problem, particularly when the liquid is corrosive in nature in that when the flow of liquid through the hole in the seal stops and the container, e.g. bottles, conduits or other liquid storing or carrying devices, to which the seal is applied is moved or shaken the residual liquid held by the raised portion surrounding the location of the puncture can flow over the raised portion and through the puncture to the exterior of the seal. Since such flow of the residual liquid only occurs when the container is moved, such flow usually occurs at an undesirable time and location e.g. when an empty container for liquid is removed from the location where the liquid is poured from the container into a desired reservoir.